Волновые процессы в микроволновой электронике
Electron bunching processes in a carcinotrode (backward_wave oscillator with self_modulation of electron emission) operating in the high_efficiency regime determined previously are investigated. The possibility of obtaining an efficiency of about 80% is explained from the physical viewpoint.
In this study with using of the small-signal theory of discrete electron-wave interaction in the passbands and stopbands resonator slow-wave systems (SWS) of power traveling-wave tubes (TWT), obtain the characteristic equation for the propagation constants of the 4-electron waves produced in the interaction of the electron beam forward and backward electromagnetic waves of SWS. The analysis of solutions of this equation, which allowed to establish the specific characteristics of these waves are compared with the known properties of electron waves in a "smooth", such as helical SWS. On the basis of solving the boundary value problem for the SWS segments were simulated and found gain of multisection TWT with transparent section and stopsection, as well as, the distribution of fields and currents along the stopsection.
In the study presents an approach to the modeling power TWT with stopband sections on the basis of the theory of discrete electron-wave interaction. Designed TWT without the use of equivalent circuits of SWS and with use of local coupling impedance and the characteristic equation of degree four.
The finitedifference theory of excitation of periodic waveguides is used to derive the characteris tic equation for electron waves formed during interaction of an electron beam with forward and counter propagating electromagnetic waves of periodic waveguides (slowwave structures). The derived characteristic equation describes interaction of electrons and waves in passbands and stopbands of periodic waveguides and contains known solutions for “smooth” slowwave structures and resonator slowwave structures near cutoff frequencies as particular cases. Several analytical solutions allowing comparison of amplification and propa gation properties of electron waves inside and at the edges of passbands and stopbands of periodic waveguides are found.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.